Most systems are pressurised (the solar system is pressurised, not necessarily the cylinder), so it’s a good idea to check the pressure gauge reading every now and then – say, once a quarter. This will fluctuate under normal operation as the system heats and cools; but if there’s a large reduction in the pressure reading, it points to a potential problem – usually a loss of heat transfer fluid somewhere. That would be unusual, but if it happens, it needs to be checked and sorted out.

Installer guarantee periods range from 1-5 years for workmanship and 2-10 years for parts. Check the guarantee carefully when you choose an installer. If you’re out of guarantee there will be a call-out charge.

If you can get your panels cleaned every few years, then it’s a good idea to do it. If your roof is at 50° and there is no TV aerial or any other potential perch near the panels, the rain may be enough to clean them. But if your roof is at a low angle, and there is an aerial above the panels, they may need to be cleaned more regularly because of bird droppings.

For much, much more information, see our book Solar Hot Water: choosing, fitting & using a system.